Let make sure people understand what electron is and what is not.
electron is a frame work.
You write code using said frame work and when compile you get NATIVE binaries.
The mac code is NATIVE, but is more than likely not optimized.
Keep in mind that turning one code to native binary is an extremely hard process. But the fact that you can develop one app and deploy on all platforms is absolutely important.
It helps keep costs down and keep all app on the same schedule and with same features.
Can it be better?
Yes. By hiring objective C developers, java and Kotlin developers and somehow sync their schedules.
Or you can have 1 developer doing code in electron and all your apps end up with the same features at the same time. This is more out of convenience/$$ than anything else.
My ipad uses about 6 to 7% of battery per hour of TR.
But if you think about it. Screen is always on, it has 3 sensors (HRM, Trainer, PM) connected and streaming data very quickly trough BT while also connected to the internet via WiFi.
You say your computer uses 8-10%. Is that per hour?
Do you have sensors?
Are you running any other app in the background?
Yes, apps that were built using Electron will be more inefficient, but not to the point of a deal break.
Now, there may be other rendering issues that can more than likely be fixed using electron. And those problems need to be reported as bug.